Belt conveyor

ABSTRACT

A belt conveyor or belt accumulator includes at least two tandem zones, each of which is defined by a motorized roller and at least one idler roller positioned along and between opposite sidewalls of the conveyor and a continuous belt routed around the motorized roller and the idler roller or rollers. The motorized roller is operable to drive the belt around the rollers to move articles along the respective zone. The belt may have a low modulus characteristic and may be initially stretched at least 0.75% in its lengthwise direction when the belt is reeved or routed around the rollers. The motorized roller of each zone may be independently operable, such as in response to an article sensor at each zone, to convey or accumulate articles on the respective zone of the belt conveyor.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority of U.S. provisionalapplications, Ser. No. 60/356,045, filed Feb. 11, 2002 by Cotter et al.,and Ser. No. 60/424,629, filed Nov. 7, 2002 by Cotter, which are herebyincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

[0002] The present invention relates generally to conveyors and, moreparticularly, to belt conveyors. The present invention also relatesgenerally to angled conveyor sections which are positioned at an anglewith respect to a conveyor or transport system to induct or dischargearticles onto or off from the conveyor or transport system.

BACKGROUND OF THE INVENTION

[0003] It is known to provide zones of rollers along a roller conveyor,where each zone includes a motorized roller and a plurality of idler orfreely rotating rollers. The motorized roller is typically operable todrive the idler rollers via a plurality of O-rings connecting eachroller to an adjacent roller in the zone. Each zone may be independentlyoperable to accumulate articles on a particular zone or zones or togenerally continuously convey articles along the zones of the rollerconveyor. However, such roller conveyors are not suitable for certainapplications where belt conveyors are desired, such as for conveyingsmall articles which may fall between the rollers or for applicationswhere a belt conveyor may be required or desired for other reasons.Also, due to the low friction between the rollers and the articles beingconveyed thereon, such roller conveyors are not suitable for providingaccumulation of articles along an inclined or declined section of theroller conveyor.

[0004] Also, it is known to provide an angled discharge junction orconnecting conveyor section at a discharge conveyor or station of asorting system. The discharge junctions typically comprise a pluralityof different length rollers rotatably mounted between a sidewall of thejunction and an angled mating or connecting frame, such that the rollersare positioned in an ascending length order to define an angled matingedge or connection at the sorting system conveyor or transport path. Therollers are typically freely rotating rollers and function to transportarticles from the transport or sorting system to a discharge conveyor orstation at the opposite end of the angled junction. Articles aredischarged from the transport system and may coast over the differentlength rollers and onto the discharge conveyor or station. It is alsoknown to provide angled belted conveyor sections where a continuous beltis reeved around rollers and is operable to induct or discharge articlesat a main conveying path or transport path. However, such angled beltedconveyor sections typically include complicated routing paths for thebelt beneath the conveyor section to properly align and track the beltaround an end roller at the angled mating edge of the angled beltedconveyor section.

SUMMARY OF THE INVENTION

[0005] The present invention provides a belt conveyor which is suitablefor continuously conveying articles along the conveyor or along segmentsor zones of the conveyor, and/or for accumulating articles on theindividual segments or zones, and may provide for accumulation ofarticles on an incline or a decline.

[0006] The present invention provides a belt conveyor which may includea plurality of segments or zones, each of which includes a continuousbelt routed around a plurality of rollers. Each of the zones of theconveyor includes a motorized roller and at least one idler roller andmay be independently operable to move articles along the belt conveyoror to accumulate articles on one or more of the zones of the beltconveyor. The present invention also provides an angled belt striproller conveyor section which is positionable at a conveyor or transportpath or system, such as a belt conveyor or a roller conveyor, to inductor discharge articles onto or off from the transport system. The angledconveyor section comprises a plurality of different length rollersarranged to define the angled mating end of the angled conveyor sectionand a plurality of different length belt strips reeved or routed orpositioned around the rollers and the motorized roller.

[0007] According to an aspect of the present invention, a belt conveyorincludes a motorized roller and at least one idler roller positionedalong and between opposite sidewalls of the conveyor and a continuousbelt reeved around the motorized roller and the idler roller or rollers.The motorized roller is operable to drive the belt around the rollers tomove articles along the belt conveyor. The belt has a low moduluscharacteristic. There may be at least approximately a 0.75% initialstretch to the belt in a lengthwise direction of the belt when the beltis reeved or positioned around the rollers. The low moduluscharacteristic of the belt may provide approximately a 2% to 4% or morestretch capability or characteristic to the belt.

[0008] The belt conveyor may comprise two or more zones, which may beindependently operable to allow for accumulation of articles at one ormore zones along the belt conveyor. Each zone may include an articlesensor, which is operable to detect articles on the belt of therespective zone, whereby the motorized roller of each zone is operablein response to the sensor and the particular application of thesegmented belt conveyor.

[0009] Optionally, the belt conveyor may be implemented at an incline ora decline, and may be operable to accumulate articles on the incline ordecline. Optionally, the belt conveyor may be operable to feed stacks oftrays to a tray destacking apparatus at an induct of a tray handlingsystem or tray management system at a mail sortation assembly. It isfurther envisioned that the belt conveyor may be implemented on anextendable loader or unloader for loading or unloading articles at atrailer or the like. Clearly, the belt conveyor may be implemented inother applications, without affecting the scope of the presentinvention.

[0010] According to another aspect of the present invention, a beltaccumulator comprises opposite sidewalls and at least two tandem zones.Each of the tandem zones comprises a motorized roller and at least oneidler roller rotatably mounted at and between the opposite sidewalls, acontinuous belt reeved around the motorized roller and the at least oneidler roller, and at least one article sensor operable to detectarticles in that zone. The continuous belt of each of the tandem zonescomprises a low modulus characteristic. The belt is initially stretchedin a lengthwise direction of the belt at least 0.75% when the belt isreeved around the rollers. The belt accumulator includes at least onecontrol which is operable to control the motorized roller of each zoneto drive the belt to convey articles along the respective zone. Thecontrol is operable to selectively and independently control themotorized rollers in response to the article sensors to provideaccumulation of articles in the zones of the belt accumulator.

[0011] According to another aspect of the present invention, a beltconveyor comprises opposite sidewalls, a motorized roller and at leastone idler roller rotatably mounted at and between the oppositesidewalls, a continuous belt reeved around the motorized roller and theidler roller or rollers, and at least one article sensor operable todetect articles on the belt. The motorized roller comprises an internalmotor operable to rotatably drive a roller portion of the rollerrelative to an axle portion of the roller. The motorized roller isoperable to drive the belt to convey articles along the belt conveyor.The motorized roller is selectively operable in response to the articlesensor or sensors.

[0012] The belt conveyor may comprise at least two tandem zones. Themotorized roller of each of the tandem zones may be operableindependently from other motorized rollers of other tandem zones toprovide accumulation of articles at one or more of the tandem zones. Themotorized roller may be selectively and independently operable inresponse to an article sensor at each zone to provide accumulation ofarticles in the zones of the belt conveyor.

[0013] The continuous belt may comprise a low modulus characteristic,which provides approximately a 1.5% or more stretch characteristic tothe belt, and may provide approximately a 2% or 4% or more stretchcharacteristic to the belt. The belt may have at least approximately a0.75% initial stretch in a lengthwise direction of the belt when thebelt is reeved or positioned around the rollers.

[0014] According to another aspect of the present invention, an angledconveyor section is configured to be positioned along a main transportpath to convey articles, which are discharged from the transport path,away from the transport path. The angled conveyor section ispositionable at an angle relative to the transport path and comprisesopposite sidewalls and an angled frame portion defining an angled matingedge of the angled conveyor for positioning adjacent to a side of thetransport path. The angled conveyor section also comprises a pluralityof rollers including a motorized roller and a plurality of idlerrollers. At least some of the idler rollers have different lengths fromthe other rollers. A plurality of belt strips are reeved around some ofthe rollers. The different length rollers are mounted to the angledframe portion and one of the sidewalls and arranged in ascending lengthorder along the angled conveyor to define an angled roller conveyingsurface. At least some of the belt strips have different lengths fromother belt strips and are reeved around the motorized roller anddifferent ones of the different length rollers. The belt strips and therollers define a belted conveying surface along the angled conveyorsection with an angled mating edge positionable adjacent to thetransport path.

[0015] The motorized roller may be positioned at an end of the angledconveyor section opposite from the angled frame portion. The motorizedroller or one or more of the other rollers may include a plurality oftracking devices operable to track the plurality of belt strips on themotorized roller. At least some of the different length rollers mayinclude corresponding tracking devices operable to track respective onesof the plurality of belt strips on the different length rollers. Thetracking devices may comprise strips or crowns around the respectiverollers.

[0016] The belt strips may have a low modulus characteristic and mayhave at least approximately a 0.75% initial stretch in their lengthwisedirection when the belt strips are reeved or positioned around therollers. The low modulus characteristic of the belt strips may provideapproximately a 2% to 4% or more stretch capability or characteristic tothe belt strips.

[0017] Therefore, the present invention provides a belt conveyor whichmay have a plurality of independently operable zones or segments, eachof which includes a continuous conveyor belt driven by a motorizedroller. The zones may operate together as a generally continuouslyrunning belt conveyor or may operate individually as an accumulatingconveyor with zone control and photo eyes or sensors. The presentinvention thus provides a zone controlled belt conveyor which mayoperate in a similar manner as a zone controlled roller conveyor, butwith a conveyor belt reeved around the motorized roller and idlerrollers rather than with multiple O-rings or the like connecting theidler rollers to the motorized roller of each zone. The belt conveyor ofthe present invention thus is capable of accumulating articles on anincline or decline. Because the motorized roller of each zone may onlycontrol or drive a small belt section or zone, the load and wear on themotorized roller is minimized to provide a longer life cycle for themotorized roller.

[0018] The angled conveyor section of the present invention provides asubstantially continuous, belted conveying surface at an angle forabutting or mating against a conveying or transport path. The angledconveyor section includes a motorized roller which is operable to drivethe different length rollers of the angled conveyor section via aplurality of different length belt strips reeved around the motorizedroller and the different length rollers of the conveyor section. Theangled conveyor section of the present invention thus provides a poweredor motorized roller and a belt conveying surface which does not requirespecial routing of the belt underneath the angled section to align thebelt with the angled mating surface or edge.

[0019] These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a top plan view of a portion of a segmented or zonedbelt conveyor in accordance with the present invention;

[0021]FIG. 2 is a side elevation of the portion of the belt conveyor ofFIG. 1;

[0022]FIG. 3 is a side elevation of a tracking roller useful with thepresent invention;

[0023]FIG. 4 is a perspective view of a belt conveyor in accordance withthe present invention;

[0024]FIG. 5 is a top plan view of the belt conveyor of FIG. 4;

[0025]FIG. 6 is a side elevation of another belt conveyor in accordancewith the present invention;

[0026]FIG. 7 is a side elevation of another belt conveyor in accordancewith the present invention;

[0027]FIG. 8 is a plan view of an angled belt strip roller conveyorsection in accordance with the present invention, as positioned at atransport path or conveyor of a sortation system;

[0028]FIG. 9 is a side elevation of the angled belt strip rollerconveyor section of FIG. 8;

[0029]FIG. 10 is an end elevation of the angled belt strip rollerconveyor section of FIGS. 8 and 9;

[0030]FIG. 11 is a sectional view of the angled belt strip rollerconveyor section taken along the line XI-XI in FIG. 8; and

[0031]FIG. 12 is a perspective view of another angled belt strip rollerconveyor section in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Referring now specifically to the drawings and the illustrativeembodiments depicted therein, a belt conveyor or belt accumulator 10includes one or more zones or segments 12 positioned along and betweenopposite sidewalls or side frames 14, and is operable to convey articlesin a direction of conveyance A (FIGS. 1 and 2). Each segment or zone 12includes a plurality of rollers 16 and a continuous belt 18 routed orreeved around the rollers 16. Each belted segment 12 may beindependently operable to accumulate articles on the segment or zone orto move articles in the direction A onto a next, adjacent segment orzone or onto another conveyor, such as another belt conveyor, a rollerconveyor, a slider bed, or the like, or any other means for receivingarticles from a discharge end of the last zone or segment of thesegmented belt conveyor 10. As best seen in FIG. 1, belt 18 may be wideenough to substantially cover the generally cylindrical roller portionsof the rollers and thus may substantially span the spacing between thesidewalls 14 to provide a wide conveying surface for conveying articlesalong the roller conveyor.

[0033] Rollers 16 of each segment or zone 12 include a motorized roller20 and one or more non-motorized or idler rollers 22. Motorized roller20 may be the lead roller of the zone or positioned at a downstream endof each segment to pull the belt 18 (and the articles supported thereon)along the respective segment 12. Motorized roller 20 may comprise a selfdriven roller with an internal motor which is operable to rotate aroller portion relative to a shaft portion of the roller, such as amotorized roller of the types commercially available from varioussources, such as Siemens Dematic Corporation, Rapistan Material HandlingAutomation Division of Grand Rapids, Mich.

[0034] For example, the roller may comprise a DC motorized roller, suchas a 12 volt DC motorized roller or the like, such as a roller of thetype disclosed in U.S. Pat. No. 6,244,427, the disclosure of which ishereby incorporated herein by reference. Optionally, the roller maycomprise a 24 volt DC motorized roller or a 42 volt DC motorized rolleror a 48 volt DC motorized roller or the like. For example, the motorizedroller may comprise a 48 volt DC motorized roller (or a 24 volt DCmotorized roller) having a diameter of approximately 50 mm and anoverall width of between 500 mm and 900 mm. The 48 volt DC motorizedroller may comprise a DC brushless motor and may be operable at speedsbetween approximately 130 rpm and 1150 rpm and may provide an output ofapproximately 3 Nm of torque at approximately 400 rpm and approximately1.5 Nm of torque at approximately 1150 rpm. It is further envisionedthat the motorized roller may comprise other DC powered motorizedrollers, or may comprise an AC powered motorized roller, such asdescribed in U.S. Pat. No. 5,442,248, the disclosure of which is herebyincorporated herein by reference, without affecting the scope of thepresent invention. The motor of the motorized roller may drive theroller directly, such as disclosed in U.S. Pat. No. 6,244,427, or maydrive the roller via a gear train or the like, such as disclosed in U.S.Pat. No. 5,442,248, the disclosures of which are hereby incorporatedherein by reference.

[0035] The motorized roller 20 thus drives the belt 18 which moves alongthe idler rollers 22, which freely rotate about their shaft portions toguide and support the belt 18 around the zone or segment 12. The idlerrollers 22 may be any type of rollers, such as conventional, freelyrotating rollers, such as the types also commercially available fromvarious sources, such as Siemens Dematic Corporation, Rapistan MaterialHandling Automation Division of Grand Rapids, Mich. Although shown ashaving multiple idler rollers along each of the zones 12, one or morezones of the segmented belt conveyor of the present invention mayinclude a support plate or slider bed between the motorized roller 20and an opposite end idler roller 22 a to support the belt 18 between theends of the zone 12, without affecting the scope of the presentinvention.

[0036] As shown in FIG. 3, end idler roller 22 a may comprise one ormore crowns or bumps 22 b along the roller to assist in tracking thebelt 18 during operation of the roller conveyor. The bumps 22 b maycomprise one or more slightly larger diameter regions of the rollerportion, such as two or three regions (or more or less depending on thelength of the roller and the particular application) having, forexample, approximately a 1-4 mm larger diameter than the diameter of thegenerally cylindrical portion of the idler roller, which may typicallyhave a diameter of approximately 50 mm. The bumps or crowns may beformed as part of the roller portion or may comprise molded portions,such as molded polyurethane portions or the like, positioned along theroller, without affecting the scope of the present invention.

[0037] Belt 18 may comprise a low modulus belt 18. In the illustratedembodiment, belt 18 has a stretch capability or characteristic of atleast approximately 1.5% stretch or more (and may have a stretchcapability or characteristic of approximately 3% to 5% stretch or more)in its lengthwise direction. Belt 18 may be initially stretched as it isreeved around the rollers, such that the belt has an initial stretch ofapproximately 0.75% or more in its lengthwise direction when positionedaround the rollers, and may be initially stretched to have an initialstretch of approximately 1% or 1.5%. Belt 18 provides a substantiallygreater amount of stretch over conventional conveyor belts, whichtypically may only provide approximately a 1% stretch characteristic orless, and typically may have an initial stretch of approximately 0.25%to 0.5% when reeved or positioned around the pulleys of a conventionalbelt conveyor. Low modulus belt 18 may be made from urethane extrusionsor urethane with polyester or nylon tension members encapsulated or maybe made from a rubber material or the like, and may be similar to thetype of belts commercially available from Nitta Corporation for use ingraphic arts and letter mail sorting. The low modulus characteristic ofbelt 18 and the approximately 0.75% or more initial stretch of belt 18allows each zone 12 of the belt conveyor 10 to be operated with littleor no take-up or adjustment being necessary to maintain the appropriatetension in the belt 18. However, such adjustment may be provided on beltconveyor 10, without affecting the scope of the present invention.

[0038] Each zone or segment 12 may also include a photo eye or sensor(not shown in FIGS. 1 and 2) for detecting articles or packages or thelike on belt 18 of the respective zone. Belt conveyor 10 may furtherinclude a control for independently operating the motorized roller 20 ofthe respective zone to move the article along segment 12 and/or totemporarily stop the movement of the article or articles to accumulatearticles on segment 12 in response to the sensor and depending on theparticular application of segmented belt conveyor 10, as discussed indetail below with respect to the conveyor 110 of FIGS. 3 and 4.

[0039] Segmented belt conveyor 10 thus may be operable to accumulatearticles on one or more of the segments or zones of the conveyor.Optionally, the segmented belt conveyor 10 may be operable on an inclineor decline and may accumulate articles on the incline or decline. It isfurther envisioned that the segmented conveyor 10 may be operable tomove articles, such as upward along an incline, as the articles arerequired by a downstream device or system. For example, the beltconveyor of the present invention may convey and feed stacks of trays toa tray destacking apparatus, such as a tray destacking apparatus of oneof the types disclosed in commonly assigned, U.S. provisionalapplications, Ser. No. 60/275,789, filed Mar. 14, 2001 by Schiesser etal. for TRAY DESTACKER (Attorney Docket RAP04 P-624); and Ser. No.60/297,516, filed Jun. 12, 2001 by Schiesser et al. for TRAY DESTACKER(Attorney Docket RAP04 P-624A), and U.S. patent application, Ser. No.10/095,829, filed Mar. 12, 2002 by Schiesser et al. for TRAY DESTACKER(Attorney Docket RAP04 P-624B), which are hereby incorporated herein byreference in their entireties. The tray destacking apparatus may beoperable to receive the stack of trays, separate and unstack eachindividual tray from the stack of trays and discharge the individualtrays to an induct of a tray handling system or tray management systemor the like, such as to an induct of a tray handling system at a mailsortation assembly. It is further envisioned that the belt conveyor ofthe present invention may be used in trailer loader or unloaderapplications, such as an extendable loader or unloader for extending theconveying surface from a support base outward and into a truck traileror the like for loading or unloading articles into or out from thetrailer, without affecting the scope of the present invention.

[0040] Referring now to FIGS. 4 and 5, a belt conveyor or beltaccumulator 110 includes a plurality of tandem zones or segments 112positioned along and between opposite sidewalls or side frames orchannels 114 and is operable to convey articles along each zone in adirection of conveyance A. Each zone 112 comprises a plurality ofrollers 116 and a continuous belt 118 routed or reeved around therollers 116. Each belted zone 112 is independently operable toaccumulate articles on the zone or to move articles in the direction Aonto a next, adjacent zone or onto another conveyor, such as anotherbelt conveyor, or a roller conveyor, slider bed, or the like, or anyother means for receiving articles from a discharge end of the last zoneof the belt conveyor 110.

[0041] In the illustrated embodiment of FIGS. 4 and 5, conveyor 110 isshown with five zones 112, with each zone 112 having a motorized roller120 and a belt 118 and a product sensor 124 positioned at an end of thezone. However, the number of zones along a conveyor section is afunction of the application and may vary without affecting the scope ofthe present invention.

[0042] Similar to rollers 16 of conveyor 10, discussed above, rollers116 of each segment or zone 112 include a motorized roller 120 and atleast one non-motorized or idler roller 122. Motorized roller 120 may bethe lead roller of the zone or may be positioned at a downstream end ofeach segment to pull the belt 118 (and the articles supported thereon)along the respective zone 112. Similar to motorized roller 20, discussedabove, motorized roller 120 may comprise a self driven roller with aninternal motor which is operable to rotate a roller portion relative toa shaft portion of the roller, such as a motorized roller of the typescommercially available from various sources, such as a 12 volt DCmotorized roller or a 24 volt DC motorized roller or a 42 volt DCmotorized roller or a 48 volt DC motorized roller or any voltage AC orDC powered motorized roller or the like. The motorized roller 120 thusdrives the respective belt 118, which moves along the idler rollers 122,which freely rotate about their shaft portions to guide and support thebelt 118 around and along the respective zone 112. The idler rollers 122may comprise any type of non-driven rollers, such as conventional,freely rotating rollers or the like, and one or more of the rollers,such as an end idler roller, may include one or more crowns or bumpstherealong to assist in tracking the belt, such as discussed above withrespect to FIG. 3.

[0043] Although shown as having multiple idler rollers along each of thezones 112, a zone 112′ of a belt conveyor 110′ (FIG. 6) or a zone 112″of a belt conveyor 110″ (FIG. 7) in accordance with the presentinvention may optionally include a slider bed between the motorizedroller 120 and an idler roller 122 or between a pair of spaced apartidler rollers 122, such as slider bed 121′ of FIG. 6, or between themotorized roller 120 and an opposite end idler roller 122 or the like,such as slider bed 121″ of FIG. 7, to support the belt 118 between therollers of the zone 112′, without affecting the scope of the presentinvention. The slider bed or beds 121′, 121″ may comprise separateplates positioned between two consecutive rollers of a zone or maycomprise a plate having a slot or opening therethrough for at least oneroller, such as a center roller of the zone, to protrude upwardpartially through the opening to provide rolling support of thecontinuous belt along the slider bed, without affecting the scope of thepresent invention.

[0044] As discussed above, belt 118 may comprise a low modulus beltwhich may provide for approximately a 0.5% or more initial stretch ormore in its lengthwise direction. In an exemplary embodiment, the beltmay provide at least approximately a 1.5% to 5% or more stretchcapability or characteristic in its lengthwise direction. In anexemplary embodiment, belt 118 may be stretched to have an initialstretch of approximately 1.5% when belt 118 is reeved around andpositioned around the rollers of the conveyor. Low modulus belt 118 maybe made from urethane extrusions or urethane with polyester or nylontension members encapsulated, or may comprise a rubber material or thelike, and may be similar to the type of belts commercially availablefrom Nitta Corporation for use in graphic arts and letter mail sorting.The initial stretch and the low modulus characteristic of belt 118allows each zone 112 of the belt conveyor 110 to be operated with littleor no take-up or adjustment being necessary to maintain the appropriatetension in the belt 118. However, such take-up or adjustment may beprovided on belt conveyor 110, without affecting the scope of thepresent invention.

[0045] Each zone or segment 112 of conveyor 110 includes a photo eye orarticle sensor 124 for detecting and/or monitoring articles or packagesor the like on belt 118 of the respective zone. Belt conveyor 110further includes a control 126 for independently operating the motorizedroller 120 of the respective zone 112 to move the article along zone 112and/or to temporarily stop the movement of the article or articles toaccumulate articles on zone 112 in response to sensor 124 and dependingon the particular application of segmented belt conveyor 110.

[0046] In the illustrated embodiment, control 126 comprises a motorcontrol 126 a at each zone 112 which is connected to each sensor 124 andthe other motor controls 126 a of the other zones. The motor controls126 a are thus in communication with one another to provide independentand synchronized or corresponding control of the motorized rollers ofeach zone, as discussed below. The motor controls 126 a are connected toa power supply (not shown) which provides power to the sensors 124 andmotor controls 126 a.

[0047] The control and photo-eyes may be operable to accumulate articleson the zones of the belt conveyor, and may be operable to individuallycontrol operation of at least some of the zones, such as by utilizingaccumulating logic and/or circuitry and the like, such as by utilizingthe accumulating logic and/or principles disclosed in U.S. provisionalapplication, Serial No. 60/412,396, filed Sep. 20, 2002 by Haan et al,for CONVEYOR SYSTEM REVERSE-SLUG ACCUMULATION (Attorney Docket SIE04P-109), which is hereby incorporated herein by reference. Articlesensors 124 may be of the type disclosed in U.S. Pat. Nos. 5,582,286 and6,253,909, and/or U.S. provisional application, Ser. No. 60/412,396,filed Sep. 20, 2002 by Haan et al, for CONVEYOR SYSTEM REVERSE-SLUGACCUMULATION (Attorney Docket SIE04 P-109), which are herebyincorporated herein by reference.

[0048] In the illustrated embodiment, each article sensor 124 comprisesa photosensor positioned at a downstream end of a respective zone 112and operable to detect products or articles as they move from thedownstream end of one zone to the upstream end of the adjacent zone. Themotorized or driven roller 120 of a particular zone may be selectivelyactivated or deactivated by control 126 in response to a correspondingarticle sensor 124, or in response to more than one of the articlesensors positioned along the conveyor, to move or stop an article orarticles that is/are present on the respective zone, as discussed below.Motorized rollers 120 thus may be directly driven and operable toselectively and independently convey or accumulate one or more articleson the associated conveyor zones in response to one or more of thearticle sensors 124.

[0049] For example, it is envisioned that the motorized rollers may beoperable in a “sleep mode”, such as described in U.S. Pat. Nos.5,582,286 and 6,253,909, the disclosures of which are herebyincorporated herein by reference. In such a mode of operation, control126 may activate the motorized roller of a particular zone in responseto an article being detected at the beginning of the zone (or at the endof the immediate upstream zone) and may deactivate the motorized rollerafter the article is moved to the next or downstream zone, such that themotorized roller of a particular zone is only activated when an articleis present at the zone and when the article is to be conveyed along thezones of the conveyor. If the downstream zones are not activated, thenthe motorized roller of the particular zone may be deactivated toaccumulate the detected article or articles on that particular zone ofthe conveyor. Such a sleep mode operation thus only activates themotorized roller of a zone when an article to be conveyed is present atthe particular zone, and thus reduces operation of the motorized rollersto increase the life cycle of the rollers.

[0050] The continuous belts of the belt conveyor of the presentinvention, and particularly the low modulus belts, may provide anincreased coefficient of friction between the conveying or carryingsurface of the belts and the products being conveyed therealong over thefriction provided by rollers of conventional roller conveyors. Thegreater frictional resistance to sliding of the articles on the beltsallows the belt conveyor of the present invention to operate at agreater speed than roller conveyors, without causing the products toslide along the zones. The greater frictional resistance also enhancesthe capability of the belt conveyor to move and accumulate articlesalong each zone individually and to move and accumulate articles oninclined or declined zones.

[0051] The belt conveyor of the present invention thus may be operableto accumulate articles on one or more of the segments or zones of theconveyor. Optionally, the belt conveyor may be operable on an incline ordecline and may accumulate articles on the incline or decline. It isfurther envisioned that the belt conveyor of the present invention maybe operable to move articles, such as upward along an incline, as thearticles are required by a downstream device or system.

[0052] Therefore, the segmented or zoned belt conveyor of the presentinvention provides a plurality of independently operable zones orsegments which may operate together as a generally continuously runningbelt conveyor or may operate individually as an accumulating conveyorwith zone control and photo eyes. The present invention thus provides azone controlled belt conveyor which may operate in a similar manner as azone controlled roller conveyor, but with a continuous belt around therollers rather than multiple O-rings or the like connecting the idlerrollers to the motorized roller of each zone. The segmented beltconveyor of the present invention thus is capable of providing foraccumulation of articles on an incline or decline. Because the motorizedroller of each zone may only control or drive a small belt section, theload and wear on the motorized roller may be minimized to provide alonger life cycle for the motorized roller.

[0053] Referring now to FIGS. 8-11, a sorting and/or conveying system210 includes a main conveyor or transport path 212 (shown in phantom inFIG. 8) and at least one angled discharge conveyor section 214positioned at an angle with respect to main conveyor 212 and operable toconvey and discharge articles from transport path 212. Angled conveyorsection 214 includes a first sidewall 216 and a second sidewall 218 andan angled frame portion 220 positioned between an end 216 a of firstsidewall 216 and an end 218 a of second sidewall 218. First sidewall 216receives or mounts a shaft end of a plurality of rollers 222, whileangled frame portion 220 and second sidewall 218 receive or mount theopposite shaft end of rollers 222, as discussed below. Angled conveyorsection 214 provides an angled mating edge along frame portion 220 toprovide an angled conveying surface at a side of transport path 212.

[0054] Sorting system 210 may include a plurality of sorting carriages(not shown) which are movable along transport path 212 and operable todischarge articles onto the angled conveyor section 214 as the articlesand carriages are transported or moved along the transport path 212. Thesorting carriages may comprise any known sorting carriages, such as tilttrays, crossbelt sorters, such as the type disclosed in U.S. Pat. No.5,588,520, which is hereby incorporated herein by reference, doublewidth crossbelt sorters, such as disclosed in U.S. pat. application,Ser. No. 09/675,237, filed Sep. 29, 2000 by Edwards et al. for DOUBLEWIDTH CROSSBELT SORTER, now U.S. Pat. No. 6,478,138 (Attorney DocketRAP04 P-611), which is hereby incorporated herein by reference, or thelike, without affecting the scope of the present invention. Alternately,transport path 212 may comprise a conveying surface having discharge ordiverting mechanisms or shoes or the like which are movable to guide ordivert articles being conveyed along the conveying surface onto theangled discharge conveyor section, without affecting the scope of thepresent invention.

[0055] Angled conveyor section 214 may be positioned with one end 214 aat an angle with respect to transport path 212, to receive articles atangled conveyor section 214. An opposite end 214 b of angled conveyorsection 214 may abut or align with another conveying surface or adischarge station or the like (not shown), without affecting the scopeof the present invention.

[0056] The rollers 222 of angled conveyor section 214 include a drivenroller or motorized roller 224 and a plurality of idler rollers 226. Theshafts of the rollers may be mounted within holes or apertures (notshown) in the sidewalls 216, 218 and/or at the mounting portions 220 aof angled frame 220, or may be mounted to the sidewalls 216, 218 and/ormounting portions 220 a via any other mounting means, without affectingthe scope of the present invention. The rollers 222 are mounted tosidewall 216 and sidewall 218 or angled frame 220 with their axes ofrotation oriented generally orthogonal to the sidewalls 216, 218 and todirection of conveyance of angled conveyor section 214.

[0057] Idler rollers 226 include multiple different length rollers, 226a, 226 b, 226 c, 226 d, 226 e, 226 f, 226 g, which are mounted betweenfirst sidewall 216 and corresponding mounting portions 220 a of angledframe 220 or sidewall 218. The different length rollers 226 a-g arearranged in ascending length order along angled conveyor section 214,such that a shortest roller 226 a is positioned toward one end of angledconveyor section 214, with the next shortest roller 226 b positionednext to shortest roller 226 a, and so on. The different length rollers226 a-g thus combine to form an angled conveying surface along angledframe 220. A single narrow roller or wheel 228 may be provided at ornear the junction of angled frame 220 and first sidewall 216 to providea conveying surface or support at that area. Depending on the desiredlength of angled conveyor section 214, one or more idler rollers 223 ofgenerally the same length as the motorized roller 224 may be mountedbetween sidewalls 216, 218 (two idler rollers 223 are shown mounted inthis manner in the illustrated embodiments of FIGS. 8-12).

[0058] Angled frame 220 extends at an angle between the ends 216 a, 218a of sidewalls 216, 218 and includes a plurality of roller mountingportions or brackets or shaft supports 220 a spaced therealong. Shaftsupports 220 a extend upward from angled frame 220 to receive the shaftends of some of the idler rollers 226, and are positioned generallybeneath the conveying surfaces of transport path 212 and angled conveyorsection 214 so as not to interfere with the conveyance of articles fromone of the conveyors to the other. Angled frame 220 and shaft supports220 a may include an upper support plate or support surface 220 b whichmay be positioned at the ends of the rollers 226 a-f and at wheel 228 toprovide support at the generally triangular area at the end of eachroller 226 and wheel 228 which would otherwise be open. This is bestshown in FIG. 13 with reference to angled conveyor section 214′,discussed below.

[0059] Angled conveyor section 214 further includes a plurality of beltstrips or tape strips 230 a-g which are routed or reeved around therollers 222 to define a belted conveying surface along angled conveyorsection 214. Each of the belt strips 230 may have a different lengthfrom the other belt strips 230 and may be routed or reeved around adifferent set of rollers than the other belt strips 230, as shown inFIG. 8. For example, a longest belt strip 230 a is routed or reevedaround driven roller 224 and shortest idler roller 226 a, while a secondlongest belt strip 230 b is routed or reeved around driven roller 224and the next shortest idler roller 226 b, and so on. The belt strips arereeved around the motorized roller and their respective end rollers andat least some of the belt strips are supported by the idler rollersand/or the other different length rollers positioned between themotorized roller and the respective end rollers.

[0060] As discussed above with respect to belt 18, belt strips 230 maycomprise a low modulus belt material. Belt strips 230 may have a stretchcapability or characteristic of at least approximately 1.5% stretch ormore (and may have a stretch capability or characteristic ofapproximately 3% to 5% stretch or more) in their lengthwise direction.Belt strips 230 may be initially stretched as they are reeved around therollers, such that the belt strips have an initial stretch ofapproximately 0.75% or more in their lengthwise direction whenpositioned around the rollers, and may be initially stretched to have aninitial stretch of approximately 1% or 1.5% or more. Low modulus beltstrips 230 may be made from urethane extrusions or urethane withpolyester or nylon tension members encapsulated or may be made from arubber material or the like, and may be similar to the type of beltscommercially available from Nitta Corporation for use in graphic artsand letter mail sorting.

[0061] In the illustrated embodiment, driven roller 224 is positioned atend 214 b of angled conveyor section 214. Driven roller 224 thus ispositioned at the discharge end of the angled conveyor section andoperable to drive the upstream rollers via the belt strips 230. However,the driven roller may be positioned elsewhere along the angled conveyorsection, and may be one of the shorter rollers mounted along the angledframe portion 220, without affecting the scope of the present invention.

[0062] Driven roller 224 may comprise a motorized roller, such as amotorized or self driven roller with a motor within the roller which isoperable to rotate the roller portion of the roller relative to theshaft portion of the roller. For example, similar to motorized roller20, discussed above, driven or motorized roller 224 may be of the typecommercially available from various sources, such as an AC poweredmotorized roller or a DC powered motorized roller, such as a 12 volt DCmotorized roller, a 24 volt DC motorized roller, a 42 volt DC motorizedroller, a 48 volt DC motorized roller or the like, as discussed abovewith respect to motorized roller 20. Motorized roller 224 drives thebelt strips or tape strips 230 around the idler rollers 223, 226, whichfreely rotate about their shaft portions in response to the movement ordriving of the tape strips 230. The idler rollers 223, 226 may compriseconventional, freely rotating rollers, such as the types alsocommercially available from various sources.

[0063] Motorized roller 224 may include a plurality of tracking members232, such as bands, crowns or crowned shells or the like, spaced alongthe motorized roller 224 for engaging and tracking the belt strips 230on motorized roller 224. Likewise, each roller 226 a-g may also includea tracking member 232, such as a band, crown or the like, at thelocation along the roller where a belt strip 230 reverses around thatparticular roller 226 a-g (in other words, a tracking member may bepositioned at each particular roller which defines an end roller orreversing roller for a respective belt strip). For example, roller 226 aincludes a tracking member 232 for belt strip 230 a, roller 226 bincludes a tracking member 232 for belt strip 230 b, and so on. Thetracking members or strips or crowns 232 are not necessary elsewherealong the rollers, since the other portions of the rollers providesupport for the belt, but do not require tracking means for tracking thebelt around the roller.

[0064] During operation, motorized roller 224 is rotatably driven, whichimparts movement of the continuous belt strips 230 and thus rotation ofidler rollers 226 to convey articles discharged from transport path 212.The rollers 222 and belt strips 230 define a generally continuousconveying path for conveying articles along angled conveyor section 214off from and away from transport path 212. Angled conveyor section 214thus provides for a powered or driven discharge roller conveyor sectionand substantially precludes articles from falling between the rollers ofthe angled induct or discharge conveyor section. Because angled conveyorsection 214 includes a driven or motorized roller, it is envisioned thatthe angled conveyor section of the present invention may comprise aninduct conveying section to a main conveyor or transport path and may beoperable to convey and induct articles from an induct station orconveyor onto carriages or onto a conveying surface of a transport orsorting system.

[0065] Referring now to FIG. 12, an angled conveyor section 214′includes a plurality of different length rollers 226′ and a plurality ofbelt strips 230 reeved around particular sets of the different lengthrollers 226′. Angled conveyor section 214′ is substantially similar toangled conveyor section 214 discussed above, such that a detaileddiscussion of the angled conveyor section will not be repeated herein.The reference numbers of angled conveyor section 214 of FIGS. 8-11 areassigned to similar or common parts of angled conveyor section 214′ inFIG. 12.

[0066] Angled conveyor section 214′ provides a different angle ofdischarge (or induct) relative to the associated transport or conveyingpath (not shown in FIG. 12), and includes a longer angled frame 220′than angled frame 220 of angled conveyor section 214, discussed above,positioned between the ends of opposite sidewalls (also not shown inFIG. 12) of the angled conveyor section 214′. Accordingly, the beltstrips 230 are routed or reeved around different length rollers 226′,whereby some of the different length rollers 226′ may not define areversing roller or end roller for a corresponding belt strip. Such anarrangement may provide for wider belt strips than may be suitable ifeach different length roller functioned as an end roller or reversingroller for a corresponding belt strip (as is the case with angledconveyor section 214 of FIGS. 8-11 and discussed above). The belt stripsare reeved around the motorized roller and their respective end rollersand at least some of the belt strips are supported by the idler rollersand/or the other different length rollers positioned between themotorized roller and the respective end rollers.

[0067] Therefore, the angled conveyor section of the present inventionprovides a substantially continuous, belted conveying surface at anangle for abutting or mating against a main conveying path. The angledconveyor section may include a motorized roller which is operable todrive the different length rollers of the angled conveyor section via aplurality of different length belt strips reeved around the motorizedroller and the different length rollers of the conveyor section. Theangled conveyor section of the present invention thus may be operable toconvey articles at a discharge of a transport path or conveying path ofa sorting or transporting system, or may be operable to convey andinduct articles onto a transport path or conveying path of a sorting ortransporting system. The angled conveyor section of the presentinvention thus provides a powered or driven or motorized roller and abelt conveying surface which does not require special routing of thebelt underneath the angled section to align the belt with the angledmating surface or edge. The belt strips are supported by some of theother different length rollers positioned between the motorized rollerand the respective end rollers to provide support of articles as theyare moved along the belt strips.

[0068] Changes and modifications in the specifically describedembodiments may be carried out without departing from the principles ofthe present invention, which is intended to be limited only by the scopeof the appended claims, as interpreted according to the principles ofpatent law.

The embodiments of the present invention in which an exclusive propertyor privilege is claimed are defined as follows:
 1. A belt conveyorhaving opposite sidewalls, said belt conveyor comprising: a motorizedroller and at least one idler roller positioned along and between theopposite sidewalls; and a continuous belt reeved around said motorizedroller and said at least one idler roller, said motorized roller beingoperable to drive said belt to move articles along said belt conveyor,said belt having a low modulus characteristic, wherein said belt isinitially stretched in a lengthwise direction of said belt at least0.75% when said belt is reeved around said rollers.
 2. The belt conveyorof claim 1, wherein said belt is initially stretched in a lengthwisedirection of said belt at least 1% when said belt is reeved around saidrollers.
 3. The belt conveyor of claim 1, wherein said belt is initiallystretched in a lengthwise direction of said belt at least 1.5% when saidbelt is reeved around said rollers.
 4. The belt conveyor of claim 1,wherein said low modulus characteristic of said belt provides at least a2% stretch characteristic to said belt.
 5. The belt conveyor of claim 1,wherein said low modulus characteristic of said belt provides at least a4% stretch characteristic to said belt.
 6. The belt conveyor of claim 1,wherein said belt has a width which spans substantially the spacingbetween said sidewalls.
 7. The belt conveyor of claim 1, wherein saidbelt comprises a plurality of belt strips reeved around said motorizedroller and said at least one idler roller.
 8. The belt conveyor of claim7, wherein said plurality of belt strips are reeved around saidmotorized roller and respective end rollers, said respective end rollerscomprising respective ones of a plurality of different length idlerrollers arranged to define an angled conveying section.
 9. The beltconveyor of claim 8, wherein at least some of said plurality of beltstrips are supported by at least one other of said different lengthrollers positioned between said motorized roller and said respective endrollers of said at least some of said plurality of belt strips.
 10. Thebelt conveyor of claim 1 including an article sensor which is operableto detect articles on said belt.
 11. The belt conveyor of claim 10including a control which is operable to control said motorized rollerin response to said article sensor.
 12. The belt conveyor of claim 1,wherein said conveyor is operable to accumulate articles on said belt.13. The belt conveyor of claim 1, wherein said belt conveyor ispositioned at one of an incline or a decline.
 14. The belt conveyor ofclaim 13, wherein said belt conveyor is operable to accumulate articleson said one of an incline or a decline.
 15. The belt conveyor of claim1, wherein said motorized roller comprises one of an AC motor, a 12 voltDC motor, a 24 volt DC motor, a 42 volt DC motor and a 48 volt DC motor.16. The belt conveyor of claim 1, wherein said motorized rollercomprises a 24 volt DC motor.
 17. The belt conveyor of claim 1, whereinsaid motorized roller comprises one of a 42 volt DC motor and a 48 voltDC motor.
 18. The belt conveyor of claim 1, wherein at least one of saidmotorized roller and said at least one idler roller has at least onecrown for tracking said belt.
 19. The belt conveyor of claim 1 includingat least one slider plate between two of said motorized roller and saidat least one idler roller for supporting said continuous belt betweenthe two rollers.
 20. The belt conveyor of claim 1 including a pluralityof spaced apart support rollers supporting said continuous belt.
 21. Abelt accumulator comprising: opposite sidewalls; at least two tandemzones, each of said at least two tandem zones comprising: a motorizedroller and at least one idler roller rotatably mounted at and betweensaid opposite sidewalls; a continuous belt reeved around said motorizedroller and said at least one idler roller, said continuous belt of eachof said tandem zones comprising a low modulus characteristic, whereinsaid belt is initially stretched in a lengthwise direction of said beltat least 0.75% when said belt is reeved around said rollers; and atleast one article sensor operable to detect articles in that zone; andat least one control, said at least one control being operable tocontrol said motorized roller of at least one of said zones to drivesaid belt to convey articles along the respective zone, said at leastone control being operable to selectively control said motorized rollersin response to said article sensors to provide accumulation of articlesin said zones of said belt accumulator.
 22. The belt accumulator ofclaim 21, wherein said at least one control is operable to control saidmotorized roller of each of said at least two tandem zones independentlyfrom other motorized rollers of other tandem zones to allow foraccumulation of articles at one or more of said at least two tandemzones.
 23. The belt accumulator of claim 21, wherein said belt isinitially stretched in a lengthwise direction of said belt at least 1%when said belt is reeved around said rollers.
 24. The belt accumulatorof claim 21, wherein said belt is initially stretched in a lengthwisedirection of said belt at least 1.5% when said belt is reeved aroundsaid rollers.
 25. The belt accumulator of claim 21, wherein said lowmodulus characteristic of said belt provides at least a 2% stretchcharacteristic to said belt.
 26. The belt accumulator of claim 21,wherein said low modulus characteristic of said belt provides at least a4% stretch characteristic to said belt.
 27. The belt accumulator ofclaim 21, wherein said belt accumulator is positioned at one of anincline or a decline.
 28. The belt accumulator of claim 27, wherein saidbelt accumulator is operable to accumulate articles on said one of anincline or a decline.
 29. The belt accumulator of claim 21, wherein saidmotorized roller of each of said at least two zones comprises one of anAC motor, a 12 volt DC motor, a 24 volt DC motor, a 42 volt DC motor anda 48 volt DC motor.
 30. The belt accumulator of claim 21, wherein saidmotorized roller of each of said at least two zones comprises a 24 voltDC motor.
 31. The belt accumulator of claim 21, wherein said motorizedroller of each of said at least two zones comprises one of a 42 volt DCmotor and a 48 volt DC motor.
 32. The belt accumulator of claim 21,wherein at least one of said motorized roller and said at least oneidler roller has at least one crown for tracking said belt.
 33. The beltaccumulator of claim 21, wherein each of said zones includes at leastone slider plate between two of said motorized roller and said at leastone idler roller for supporting said continuous belt of the respectivezone between the two rollers.
 34. The belt accumulator of claim 21,wherein each of said zones includes a plurality of spaced apart supportrollers supporting said continuous belt.
 35. The belt accumulator ofclaim 21, wherein said belt has a width which spans substantially thespacing between said sidewalls.
 36. An angled conveyor sectionconfigured to be positioned along a main transport path to conveyarticles discharged from the transport path away from the transportpath, said angled conveyor section being positionable at an anglerelative to the transport path and comprising: opposite sidewalls and anangled frame portion defining an angled mating edge of said angledconveyor for positioning adjacent to a side of the transport path; aplurality of rollers including a motorized roller and a plurality ofidler rollers, at least some of said rollers having different lengthsfrom other rollers, said different length rollers being mounted to saidangled frame portion and one of said sidewalls and arranged in ascendinglength order along said angled conveyor to define an angled rollerconveying surface; and a plurality of belt strips, at least some of saidbelt strips having different lengths from the other belt strips andbeing reeved around said motorized roller and respective end rollers,said respective end rollers comprising different ones of said differentlength rollers, said belt strips and said rollers defining a beltedconveying surface along said angled conveyor section with an angledmating edge positionable adjacent to the transport path.
 37. The angledconveyor section of claim 36, wherein said belt strips comprise a lowmodulus belt strip material.
 38. The angled conveyor section of claim37, wherein said belt strips are initially stretched in a lengthwisedirection of said belt strips at least 0.75% when said belt strips arereeved around said rollers.
 39. The angled conveyor section of claim 37,wherein said belt strips are initially stretched in a lengthwisedirection of said belt strips at least 1% when said belt strips arereeved around said rollers.
 40. The angled conveyor section of claim 37,wherein said belt strips are initially stretched in a lengthwisedirection of said belt strips at least 1.5% when said belt strips arereeved around said rollers.
 41. The angled conveyor section of claim 37,wherein said low modulus belt material of said belt strips provides atleast a 2% stretch characteristic to said belt strips.
 42. The angledconveyor section of claim 37, wherein said low modulus belt material ofsaid belt strips provides at least a 4% stretch characteristic to saidbelt strips.
 43. The angled conveyor section of claim 36, wherein saidbelt strips are movably supported by said rollers.
 44. The angledconveyor section of claim 36, wherein at least some of said belt stripsare supported by at least one of said different length rollerspositioned between said motorized roller and said respective end rollersof said at least some of said belt strips.
 45. The angled conveyorsection of claim 36, wherein said motorized roller is positioned at anend of said angled conveyor section opposite from said angled frameportion.
 46. The angled conveyor section of claim 36, wherein saidmotorized roller includes a plurality of tracking devices operable totrack said plurality of belt strips on said motorized roller.
 47. Theangled conveyor section of claim 46, wherein at least some of saiddifferent length rollers include corresponding tracking devices operableto track respective ones of said plurality of belt strips on saiddifferent length rollers.
 48. The angled conveyor section of claim 47,wherein said tracking devices comprises at least one of strips andcrowns around the respective rollers.
 49. The angled conveyor section ofclaim 36, wherein said motorized roller is operable to drive said beltstrips to receive discharged articles from said transport path and totransport the discharged articles away from said transport path.
 50. Theangled conveyor section of claim 36, wherein said motorized roller isoperable to drive said belt strips to transport articles toward saidtransport path and to induct the articles onto said transport path. 51.The angled conveyor section of claim 36, wherein said motorized rollercomprises one of an AC motor, a 12 volt DC motor, a 24 volt DC motor, a42 volt DC motor and a 48 volt DC motor.
 52. The angled conveyor sectionof claim 36, wherein said motorized roller comprises a 24 volt DC motor.53. The angled conveyor section of claim 36, wherein said motorizedroller comprises one of a 42 volt DC motor and a 48 volt DC motor. 54.The angled conveyor section of claim 36, wherein said different lengthrollers are arranged with an aligned end of said different lengthrollers being mounted to and aligned along one of said sidewalls and anopposite end of said different length rollers being mounted to saidangled frame portion.